WO2010050718A2 - Appareil et procédé de formation de faisceaux coopérative dans un système de communication sans fil - Google Patents

Appareil et procédé de formation de faisceaux coopérative dans un système de communication sans fil Download PDF

Info

Publication number
WO2010050718A2
WO2010050718A2 PCT/KR2009/006214 KR2009006214W WO2010050718A2 WO 2010050718 A2 WO2010050718 A2 WO 2010050718A2 KR 2009006214 W KR2009006214 W KR 2009006214W WO 2010050718 A2 WO2010050718 A2 WO 2010050718A2
Authority
WO
WIPO (PCT)
Prior art keywords
base station
channel
serving
neighbor
pmi
Prior art date
Application number
PCT/KR2009/006214
Other languages
English (en)
Other versions
WO2010050718A3 (fr
Inventor
Jin Kyu Han
Joon Young Cho
Ju Ho Lee
Original Assignee
Samsung Electronics Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Samsung Electronics Co., Ltd. filed Critical Samsung Electronics Co., Ltd.
Priority to US13/126,351 priority Critical patent/US9055448B2/en
Publication of WO2010050718A2 publication Critical patent/WO2010050718A2/fr
Publication of WO2010050718A3 publication Critical patent/WO2010050718A3/fr

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems

Definitions

  • the present invention relates to wireless communications and, in particular, to a cooperative beamforming apparatus and method in a wireless communication system supporting channel sensitive scheduling based on feedback information.
  • Cellular structure is a basic principle for the configuration of the radio subsystem of a mobile communication system, and the service coverage of the system can be expanded by addition of base stations.
  • SINR Interference and Noise Ratio
  • the cellular communication system supports handover from the serving base station to a neighbor base station to secure user mobility.
  • handovers There are two types of handovers: hard handover in which a connection is broken before a new radio connection is established between the mobile station and the base station and soft handover in which a new radio connection is established before the old connection is broken between the mobile station and the base station.
  • CDMA Code Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • LTE Long Term Evolution
  • 3GPP 3 rd Generation Partnership Project
  • a base station can receive the signal transmitted by a mobile station served by another base station, if it knows the channelization code of the mobile station.
  • OFDMA Orthogonal Frequency Division Multiple Access
  • multiple base stations have to share the resource allocation information for allocating the same frequency and time resources to a single mobile station. That is, the early OFDMA-based 4G system is designed under the assumption of hard handover in consideration of the costly commu- nication between the base stations.
  • Cooperative network is a concept in which multiple base stations cooperate to support single mobile station based on the shared information.
  • distribute network is a network architecture operating without information exchange among base stations.
  • the cooperative networks can be classified depending on the information level exchanged between the base stations. If multiple base stations share the information destined to the same mobile station, it is possible to implement a cooperative network to transmit the data to the mobile station simultaneously. If multiple base stations share the information on the frequency and time resources and power allocated to a mobile station but not the data destined to the mobile station, it is possible to implement a cooperative network to avoid inter-cell interferences. In the former case, the information amount exchanged between the base station increases, but equivalent channel condition is improved from the viewpoint of the mobile station. In the latter case, it is difficult to expect the improvement of the equivalent channel condition to that extent in the former case, but any improvement with the cost of tiny increase of information exchange between the base stations.
  • beamforming is a technique to improve the equivalent channel condition of the user by applying beamforming weights to multiple antennas of the base station individually for optimal channel of the user.
  • the beamforming weights have to be adjusted individually in adaptation to the time- varying channel characteristics.
  • the base station can compute the beamforming weights.
  • the base station can compute the appropriate beamforming weights of the antennas using the reference signals transmitted by the mobile station for demodulation.
  • the base station has to receive feedback signal transmitted by the mobile station for acquiring the spatial characteristics of the channel.
  • FDD Frequency Division Duplex
  • the feedback information transmitted by the mobile station for supporting beamforming weight computation of the base station includes Channel Matrix Indicator (CMI) and Precoding Matrix Indicator (PMI). Since the base station is provided with plural transmit antennas, the channel conditions are expressed in the form of vector or matrix.
  • the feedback information is quantized to improve the reliability such that a channel matrix set composed of a predetermined number of elements representing the channel vectors or matrices is defined.
  • the mobile station selects a channel vector or matrix indicative of its channel condition from the channel matrix set and reports the CMI indicating the selected channel vector or matrix to the base station.
  • the PMI is fed back to report the user preference beamforming weights.
  • the mobile station selects an element from a beamforming weight matrix composed of a predetermined number of elements representing the beamforming weight available for the base station and reports the PMI indicating the selected beamforming weight to the base station.
  • FIG. 1 is a schematic diagram illustrating a transmission beamforming in a conventional distributed network cellular structure.
  • the mobile station 105 is connected to the base station 101
  • the mobile station 107 is connected to the base station 103
  • the base stations 101 and 103 do not share the information related to the beamforming and resource allocation.
  • the base station 101 forms its beam as denoted by reference numeral 111 to transmit a signal to the mobile station 105
  • the base station 103 forms its beam as denoted by reference numeral 113 to transmit a signal to mobile station 107. Since the two base stations 101 and 103 do not share information, the beam 111 and 113 are formed independently. In this case, the base station 101 focus the beam 111 to improve the SINR for the mobile station 105, however, the beam 111 may be influenced by the beam 111 formed by the base station 103.
  • the signal transmitted by the base station 103 can act as storing interference to the mobile station 105, whereby the SINR improvement effect of the beam 111 is nullified. This means that the independent beamforming of the base stations do not guarantee the SINR improvement for the mobile station.
  • FIG. 2 is a schematic diagram illustrating a transmission beamforming in a conventional cooperative network cellular structure.
  • the mobile stations 107 and 207 are connected to the base station 103.
  • the base station 101 schedules the mobile station 105 to form the beam 111.
  • the base station 103 forms a beam for transmitting signal to the mobile station 107
  • the beam focused to the mobile station 107 is likely to make interference to signal transmitted from the base station 101 to the mobile station 105 as in FIG. 1.
  • a cluster controller 201 controls the scheduling operations of the two base stations 101 and 103, such that the two base stations 101 and 103 can perform scheduling and beamforming without interfering with each other.
  • the cluster scheduler 201 can be located near the base station 101 or 103 geographically or at a remote place.
  • the cluster scheduler 201 makes a determination for interference-free scheduling, power allocation, and beamforming and reports the determination result to the base stations under the control of the cluster scheduler 201.
  • the term cluster means a set of the base stations under the control of the scheduler.
  • FIG. 3 is a sequence diagram illustrating operations of network elements in a distributed network cellular structure of FIG. 1 for channel sensitive scheduling.
  • the mobile station 301 is connected to the base station 303.
  • the mobile station 301 sends channel condition information such as Channel Quality Indicator (CQI) and Precoding Matrix Indicator (PMI) to the base station 303 (305).
  • CQI Channel Quality Indicator
  • PMI Precoding Matrix Indicator
  • the base station 303 receives the feedback information such as the CQI and/or PMI from all the mobile stations within the cell, generates resource allocation and beamforming information based on the feedback information, and sends the resource allocation and beamforming information to the mobile station 301 in the form of control information.
  • FIG. 4 is a sequence diagram illustrating operations of network elements in a cooperative network cellular structure of FIG. 2 for channel sensitive scheduling.
  • the mobile station 301 is connected to the base station 303.
  • the mobile station 301 sends channel condition information such as CQI and PMI to the base station 303 in order for the base station to perform channel sensitive scheduling and beamforming in consideration of the interference with neighbor base station 403 (405).
  • channel condition information such as CQI and PMI
  • two types of PMIs can be transmitted: one intended to be used by serving base station 303 and the other intended not to be used by the neighbor base station 403.
  • the serving base station 303 collects the feedback information transmitted by the mobile stations within the cell and delivers the feedback information to the cluster scheduler 401 (407).
  • the neighbor base station 403 also collects the feedback information transmitted by the mobile stations within its cell and delivers the feedback information to the cluster scheduler 401 (409).
  • the cluster scheduler 401 generates downlink scheduling information including scheduling, resource allocation, and beamforming parameters for the base stations 303 and 403 under its control and sends the downlink scheduling information to the base stations 303 and 403 (411).
  • the base station 303 Upon receipt of the downlink scheduling information, the base station 303 sends the control information generated based on the downlink scheduling information to the mobile station 301 along with the transmission signal (413).
  • the conventional cooperative network does not help improving the uplink SINR of the mobile station at the cell boundary area.
  • Fur- thermore, transmitting additional feedback information, i.e. PMI intended not to be used by the neighbor base station, as well as the CQI and PMI intended to be used by the serving base station must be burdensome from the viewpoint of the mobile station located at the cell boundary area. That is, the conventional cooperative network must pay significant cost in uplink direction for improving the SINR in downlink direction. Disclosure of Invention Technical Problem
  • the present invention provides a cooperative beamforming apparatus and method that is capable of improving SINR in downlink direction without increasing feedback amount.
  • the present invention provides a cooperative beamforming apparatus and method that is capable of achieving cooperative beamforming gain without costly cooperative network implementation by providing a PMI intended not to be used in the neighbor base station to the corresponding neighbor base station.
  • a beamforming method in a wireless communication system includes transmitting, at a mobile station, a channel condition information of a channel of a serving base station to the serving base station and a channel condition information of a channel of a neighbor base station; and forming, at the serving base station, a beam based on the channel condition information to transmit a signal and, at the neighbor base station, a beam based on the channel condition information to transmit a signal.
  • a beamforming method in a wireless communication system includes transmitting, from a mobile station, a channel condition information of a serving base station to the serving base station and a channel condition of a neighbor base station to the neighbor base station; forwarding the channel condition informations from the serving and neighbor base stations to a scheduler; delivering a beamforming decision made based on the channel condition information from the scheduler to the serving and neighbor base stations; and forming, at the serving and neighbor base stations, beams based on the beamforming decision respectively.
  • a feedback method of a mobile station for beamforming in a wireless communication system includes estimating, when a signal is received, channels of a serving base station and a neighbor base station and measuring channel qualities of the serving and neighbor base stations; and reporting the channel quality of the serving base station to the serving base station and the channel quality of the neighbor base station to the neighbor base station.
  • a feedback device of a mobile station for supporting beamforming in a wireless communication system includes a received signal processor which processes signals received from a serving base station and a neighbor base station; a serving cell condition measurer which measures a channel condition of the serving base station based on the signal received from the serving base station; a neighbor cell condition measurer which measures a channel condition of the neighbor base station based on the signal received from the neighbor base station; and a transmission signal processor which transmits the channel condition of the serving base station to the serving cell and transmits the channel condition of the neighbor base station to the neighbor base station.
  • the cooperative beamforming apparatus and method of the present invention is advantageous to perform a cooperative network-based cooperative beamforming in downlink direction without increase feedback burden of mobile stations.
  • the cooperative beamforming apparatus and method of the present invention is advantageous to perform a distributed network-based cooperative beamforming in downlink direction without cooperation between the base stations by allowing the mobile stations to report a negative PMI, which is intended not to be used by neighbor base stations, to the neighbor base stations.
  • FIG. 1 is a schematic diagram illustrating a transmission beamforming in a conventional distributed network cellular structure
  • FIG. 2 is a schematic diagram illustrating a transmission beamforming in a conventional cooperative network cellular structure
  • FIG. 3 is a sequence diagram illustrating operations of network elements in a distributed network cellular structure of FIG. 1 for channel sensitive scheduling
  • FIG. 4 is a sequence diagram illustrating operations of network elements in a cooperative network cellular structure of FIG. 2 for channel sensitive scheduling
  • FIG. 5 is a sequence diagram illustrating operations of network elements of a wireless communication system for channel sensitive scheduling and cooperative beamforming according to an exemplary embodiment of the present invention
  • FIG. 6 is a sequence diagram illustrating operations of network elements of a wireless communication system for channel sensitive scheduling and cooperative beamforming according to another exemplary embodiment of the present invention
  • FIG. 7 is a diagram illustrating a principle to allocate resource for reporting negative
  • FIG. 8 is a block diagram illustrating a configuration of a mobile station for supporting the cooperative beamforming technique according to an exemplary embodiment of the present invention.
  • FIG. 9 is a block diagram illustrating a configuration of a base station for supporting the cooperative beamforming technique according to an exemplary embodiment of the present invention.
  • Mode for the Invention
  • Wireless communication systems are evolving to meet the requirements for wireless packet data communication system for high speed and high quality multimedia services including data and video as well as convention voice.
  • various wireless communication standards and technologies such as High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA) of the 3 rd Generation Partnership Project (3GPP), High Rate Packet Data (HRPD) of 3GPP2, and 802.16x of Institute of Electrical and Electronics Engineers (IEEE) have been developed for supporting high speed and high quality radio packet data communication services.
  • HSDPA High Speed Downlink Packet Access
  • HSUPA High Speed Uplink Packet Access
  • HRPD High Rate Packet Data
  • IEEE Institute of Electrical and Electronics Engineers
  • the 3G wireless packet data communication systems including HSDPA, HSUPA, and HRPD use Adaptive Modulation and Coding (AMC) and channel sensitive scheduling techniques for improving transmission efficiency.
  • AMC Adaptive Modulation and Coding
  • the transmitter can adjust the data amount to be transmitted according to the channel status. That is, the AMC enables reducing the transmission data amount in a bad channel condition to decrease the reception error probability to some extent and increasing the transmission data amount in a good channel condition to maximize the transmission rate while maintaining the reception error probability to the extent.
  • the channel sensitive scheduling technique enables the transmitter to serve the user equipment having the best channel condition among plural user equipments so as to maximize the system throughput. Such system throughput improvement is achieved by multi-user diversity gain.
  • the ACM and channel sensitive scheduling methods allows the transmitter to select the modulation and coding scheme at the best timing based on the partial channel information fed back by the receiver.
  • OFDMA-based evolved communication technologies are in the middle of standardization in both 3GPP and 3GPP2.
  • the OFDMA technology is superior to the CDMA technology in system throughput.
  • One of the main factors increasing throughput of OFDMA-based system is a frequency domain scheduling.
  • the frequency domain scheduling can achieve further throughput gain by using the frequency-varying characteristic.
  • a base station can allocate the resources including the frequency, time, and power in adaptation to the channel conditions of multiple users.
  • the user equipments In order to support the adaptive resource allocation, it is required for the user equipments to report channel conditions based on the reference signal transmitted by the base station. Such a channel condition reporting process is called CQI feedback.
  • the adaptive resource allocation is implemented with appropriate CQI feedback mechanism.
  • the frequency selective scheduling is implemented with a band-specific CQI feedback in which the channel quality of a specific frequency band of a system bandwidth is reported.
  • a beam-specific CQI feedback in which the channel condition of a specific beamforming is reported is appropriate for space selective scheduling.
  • the cooperative beamforming technique is directed to a wireless communication system in which the mobile station feeds back the CQI and PMI in the following description, the present invention is not limited thereto.
  • the cooperative beamforming technique of the present invention can be applied to a wireless communication in which the mobile terminal reports quantized channel value as the feedback information.
  • the mobile station reports channel quality information such as CQI and PMI in order for the serving base station to perform a channel sensitive scheduling and beamforming in consideration of the interference suppression between the serving and neighbor base stations.
  • channel quality information such as CQI and PMI
  • PMI channel quality information
  • the first PMI is a positive PMI that is intended to be used by the serving base station
  • the second PMI is a negative PMI that is intended not to be used by the neighbor base station.
  • the negative PMI is the feedback information for suppressing interference from the neighbor base station, and it can be replaced by a neighbor- specific positive PMI, i.e. a PMI that is intended to be used by the neighbor base station.
  • the feedback of a negative PMI means that the negative PMI-based beamforming of the neighbor base station causes significant interference to the mobile station
  • the feedback of a neighbor- specific positive PMI means that the positive PMI-based beamforming of the neighbor base station suppresses the interference to the mobile station.
  • the cooperative beamforming technique is described with the use of the negative PMI.
  • the negative PMI can be replaced by the neighbor-specific positive PMI.
  • a channel information feedback mechanism is proposed to improve the communication performance of the mobile station experiencing bad channel condition at the cell boundary area with the cooperation of base stations.
  • the mobile station reports a PMI that is intended not to be used by the neighbor base station (negative PMI) as well as the CQI and PMI that is intended to be used by the serving base station (positive PMI). Since the uplink channel condition at the cell boundary is not improved even when the cooperative beamforming is adopted, the negative PMI as additional feedback information is burdensome.
  • the mobile station reports the CQI and positive PMI to the serving base station and the negative PMI to the neighbor base station in order to mitigate the serving base station-centric feedback burden at the cell boundary area. Since the feedback burden is distributed, it is possible to achieve the cooperative beamforming gain while reducing the serving base station-centric feedback burden. Furthermore, the cooperative beamforming technique according to an exemplary embodiment of the present invention can be implemented without cooperation between base stations, thereby simplifying network structure.
  • FIG. 5 is a sequence diagram illustrating operations of network elements of a wireless communication system for channel sensitive scheduling and cooperative beamforming according to an exemplary embodiment of the present invention.
  • the mobile station sends the neighbor base station a PMI that is intended not to be used by the neighbor base station (negative PMI).
  • the base station 501 reports the CQI and positive PMI to the service base station 503 (531) and the negative PMI to the neighbor base station 507 (533).
  • the serving base station 503 Upon receipt of the CQI and positive PMI, the serving base station 503 forwards the CQI and positive PMI to the cluster scheduler 505 (537). Also, the neighbor base station 507 forwards the negative PMI received from the mobile station 501 to the cluster scheduler 505 (539).
  • the PMI transmitted by the serving base station 503 is the positive PMI that is intended to be used by the serving base station 503, and the PMI transmitted by the neighbor base station 507 is the negative PMI that is intended not to be used by the neighbor base station 507.
  • the cluster scheduler 505 collects the feedback information of the mobile stations that are transmitted by the base stations 503 and 507 under its control and generates downlink scheduling information related to the scheduling, resource allocation, and beamforming per base station. Next, the cluster scheduler 505 sends the downlink scheduling information to the respective base stations 505 and 507 (541). If the downlink scheduling information is received, the serving base station 503 sends the control information generated based on the downlink scheduling information to the mobile station 501 along with the transmission signal (543).
  • FIG. 6 is a sequence diagram illustrating operations of network elements of a wireless communication system for channel sensitive scheduling and cooperative beamforming according to another exemplary embodiment of the present invention.
  • the mobile station sends the neighbor base station a PMI that is intended not to be used by the neighbor station (negative PMI), and the network is structured in a distributed network architecture without involvement of a cluster scheduler.
  • the mobile station a 601 is connected to the base station A 603, and the mobile station b 607 is connected to the base station B 605.
  • the mobile station a 601 reports its feedback information including a CQI and a positive PMI to its serving base station A 603 (651), and the mobile station b 607 reports its feedback information including a CQI and a positive PMI to its serving base station B 605 (655).
  • the mobile station a 601 sends the base station B 605 a negative PMI that is intended not to be used by a neighbor base station (653).
  • the mobile station b 607 can send the base station A 603 a negative PMI that is intended not to be used by a neighbor base station.
  • each base station receives the CQI and positive PMI from the mobile stations within the serving cell and the negative PMI from the base stations within the neighbor cell and makes a decision for scheduling and beamforming based on these CQI and positive and negative PMIs by itself without involvement of a cluster scheduler. Accordingly, the base station A 603 makes a decision for scheduling and beamforming based on the feedback information (here, the positive PMI) and sends the control information containing the decision result to the mobile station a 601 along with a transmission signal (657).
  • the feedback information here, the positive PMI
  • the base station B 605 makes a decision for scheduling and beamforming based on the feedback information (here, the positive PMI received from the mobile station b 607 and the negative PMI received from the mobile station a 601) and sends the control information containing the decision result to the mobile station b 607 (661).
  • the base station B 605 makes the scheduling and beamforming decision with the in consideration of the negative PMI received from the mobile station a 601 such that the negative PMI is excluded to make its beamforming decision.
  • FIG. 7 is a diagram illustrating a principle to allocate resource for reporting negative
  • the information on the feedback resource depicted in FIG. 7 can be stored in the storage device of the mobile station.
  • a resource 701 is allocated for feedback to a base station A
  • a resource 703 is allocated for feedback to a base station B.
  • the feedback resources can be the frequency and time resources or code resources identified by channelization codes.
  • the feedback resources can be allocated per mobile station or commonly allocated to all the mobile stations within the cluster. In the former case, the base station can identify the mobile station reported the feedback information and the serving cell of the mobile station to support the cooperative beamforming based on the cooperative network structure. In the latter case, the base station cannot identify the mobile station reported the feedback information but support the cooperative beamforming based on the distributed network structure.
  • Each of the resources 701 and 703 is mapped to a set of beamforming vectors
  • a mobile station wants the base station A to not use a beamforming vector 2, it transmit the beamforming vector 1 using a resource element 712 of the resource 701.
  • the base station can identify the beamforming vector which is intended not to be used based on the resource element in which a signal is received.
  • the resource elements 710, 411, 712, and 414 of the resource 701 that are mapped to the beamforming vectors can be the frequency, time, or channelization code indices.
  • the mobile stations transmit the beamforming vectors that are not intended to be used by neighbor base stations using the commonly shared resources. If a predetermined level of energy is detected at a specific resource, the base station can recognize that the mobile stations within the neighbor cell want it to do not use the beamforming vector mapped to the specific resource. In this case, it is not required for the base station to know which mobile station has sent the negative feedback information. The more a number of mobile stations sending the negative feedback information with the same resource is, the higher the energy level of the resource is.
  • the feedback resources for sending negative feedback information to the neighbor cells within the cluster is predefined and shared by the base stations under the control of the cluster.
  • the feedback resource structure is provided by higher layer signaling in the mobile station prior to the configuration of the feedback channel.
  • FIG. 8 is a block diagram illustrating a configuration of a mobile station for supporting the cooperative beamforming technique according to an exemplary embodiment of the present invention.
  • the mobile station includes an antenna 801, a received signal processor 803, a serving cell channel estimator 805, a serving cell PMI selector 807, a CQI generator 809, a serving cell feedback generator 811, a neighbor cell channel estimator 815, a neighbor cell PMI selector 817, a neighbor cell feedback generator 821, a data/control information generator 825, a multiplexer 831, and a transmission signal processor 835.
  • the antenna 801 receives the signals transmitted by the base stations.
  • the received signal processor 803 extracts the reference signals of the serving base station and the neighbor base stations from the signal signals.
  • the serving cell channel estimator 805 estimates the channel of the serving base station from the output of the received signal processor 803.
  • the serving cell PMI selector 807 selects a positive PMI to be reported to the serving base station based on the output of the serving cell channel estimator 805.
  • the CQI measure 809 measures the CQI to be reported to the service base station based on the output of the service cell channel estimator 803.
  • the neighbor cell channel estimator 815 estimates the channel of the neighbor base station form the output of the received signal processor 803.
  • the neighbor cell PMI selector 817 selects a negative PMI to be reported to the neighbor base station based on the output of the neighbor cell channel estimator 815.
  • the serving cell feedback generator 811 generates the first feedback information to be reported to the serving cell based on the outputs of the serving cell PMI selector 807 and the CQI generator 809.
  • the neighbor cell feedback generator generates the second feedback information to be reported to the neighbor cell based on the outputs of the neighbor cell PMI selector 817.
  • the data/control information generator 825 generates data and other control information to be transmitted to the serving base station.
  • the multiplexer 831 multiplexes the first feedback information output by the serving cell feedback generator 811, the second feedback information output by the neighbor cell feedback generator 821, and the data and control information output by the data/ control information generator 825 into a transmission signal.
  • the transmission signal processor 835 superimposes the transmission signal output by the multiplexer 831 on a radio frequency (RF) signal and then transmits the RF signal through the antenna 801.
  • RF radio frequency
  • the mobile station receives the signals transmitted by the base stations and generates the first and second feedback information.
  • the signal received by means of the antenna is transferred to the received signal processor 803.
  • the received signal processor 803 extracts the reference signals of the service base station and the neighbor base stations and outputs the reference signals to the serving base station channel estimator 805 and the neighbor base station channel estimator 815.
  • the serving cell channel estimator 805 estimates the channel of the service base station and outputs the estimated channel value to the CQI generator 809 and the serving cell PMI selector 807.
  • the CQI generator 809 measures the serving base station channel indicated by the estimated channel value and outputs the CQI to the serving cell feedback generator 811 in the form of a CQI.
  • the serving cell PMI selector 807 selects a PMI for the channel indicated by the estimated channel value and outputs the selected PMI as the positive PMI, which is intended to be used by the serving cell, to the serving cell feedback generator 811.
  • the serving cell feedback generator 811 generates the first feedback information containing the CQI of positive PMI.
  • the neighbor cells channel estimator 815 estimates the channel of the neighbor base station and outputs the estimated channel value to the neighbor cell PMI selector 817.
  • the neighbor cell PMI selector 817 selects a PMI for the channel indicated by the estimated channel value and outputs the selected PMI as the negative PMI, which is intended not to be used by the neighbor base station, to the neighbor cell feedback generator 821.
  • the neighbor cell feedback generator 821 generates the second feedback information containing the negative PMI.
  • the data and control information to be transmitted to the serving base station are generated by the data/control information generator 825.
  • the first feedback information output by the serving cell feedback generator 811, the second feedback information output by the neighbor cell feedback generator 821, and the data and control information output by the data/control information generator 825 are multiplexed into a transmission signal by the multiplexer 831 and then output to the transmission signal processor 835.
  • the transmission signal is superimposed on the RF signal to be transmitted through the antenna 801.
  • the mobile station generates and transmits the first feedback information to the serving base station as indicated by reference numeral 531 of FIG. 5 or 651 of FIG. 6; and generates and transmits the second feedback information to the neighbor base station as indicated by reference numeral 533 of FIG. 5 or 653 of FIG. 6.
  • the mobile station is provided with a storage means (not shown) for storing the feedback resources so as to generate first feedback information with the positive PMI transmitted to the service base station and the second feedback information with the negative PMI transmitted to the neighbor base stations.
  • FIG. 9 is a block diagram illustrating a configuration of a base station for supporting the cooperative beamforming technique according to an exemplary embodiment of the present invention.
  • the base station includes an antenna 901, a received signal processor 903, a demultiplexer 905, a data/control information demodulator/decoder 907, an in-cell CQI/PMI receiver 911, a out-cell PMI receiver 913, a scheduler 915, a data/control information generator 917, a multiplexer 919, and a transmission signal processor 921.
  • the antenna 901 receives the radio frequency signal transmitted by mobile stations.
  • the received signal processor 903 converts the received radio frequency signal to a baseband signal.
  • the demultiplexer 905 demultiplexes the output of the received signal processor 903 into the data/control information, the first feedback information and/or the second feedback information.
  • the demodulator/decoder 907 demodulates and decodes the data and control information output by the demultiplexer 905.
  • the CQI/PMI receiver 911 extracts the CQI/PMI from the output of the demodulator
  • the CQI/PMI can be the first feedback information, and the PMI of the first feedback information is the positive PMI.
  • the out-cell PMI receiver 913 extracts the PMI from the output of the demodulator 905.
  • the PMI can be the negative PMI carried by the second feedback information.
  • the scheduler 915 makes a scheduling and beamforming decision base on the output of the in-cell CQI/PMI receiver 911, the PMI receiver 913, and data/control information demodulator/decoder 907.
  • the data/ control information generator 917 generates multi-user data and control information based on the scheduling and beamforming decision made by the scheduler 915.
  • the multiplexer 919 multiplexes the multi-user data and control information into transmission signals.
  • the transmission signal processor 921 superimposes the transmission signals on the RF signals to be transmitted through the antenna 901.
  • the base station analyzes the first feedback information transmitted by the mobile stations within its cell and the second feedback information transmitted by the mobile station within the neighbor cell and controls the beamforming to the mobile station within its cell.
  • the radio frequency signal received by the antenna 901 is output to the received signal processor 903.
  • the radio frequency signal is converted to the baseband signal by the received signal processor 903, and the baseband signal is output to the demultiplexer 905.
  • the base band signal id demultiplexed into the data and control information, the first feedback information and/or the second feedback information by the demultiplexer 905.
  • the data and control information are output to the data/control information demodulator/decoder 907 so as to be demodulated and decoded into the original data and control information by the data/control information demodulator/ decoder 907.
  • the first feedback information is output to the in-cell CQI/PMI receiver 911 such that the in-cell CQI/PMI receiver 911 extracts the CQI and positive PMI from the first feedback information.
  • the second feedback information is output to the out- cell PMI receiver 913 such that the out-cell PMI receiver 913 extracts the negative PMI from the second feedback information.
  • the scheduler 915 can be placed at the base station in the distributed network-based communication system as shown in FIG. 6 or implemented as a cluster scheduler outside the base station in the cooperative network-based communication system as shown in FIG. 5.
  • the scheduler 915 is responsible for making a scheduling and beamforming decision and provides the decision result to the data/control information generator 917.
  • the data/control information generator 917 generates the data and control information based on the decision result provided by the scheduler 915.
  • the data and control information generated by the data/control signal generator 917 are multiplexed into transmission signals by the multiplexer 919. Finally, the multiplexed transmission signals are superimposed on the radio frequency signals by the transmission signal processor 921 and then transmitted through the antenna 901.
  • the mobile station 501 first receives the signals transmitted by the serving base station 503 and the neighbor base station 507. Upon receiving the signals from the serving and neighbor base stations 503 and 507, the mobile station 501 generates the first feedback information and the second feedback information. At this time, the received signal processor 803 of the mobile station 503 extracts the reference signals of the serving and neighbor base stations 503 and 507 from the received signals and outputs the extracted reference signals to the serving cell channel estimator 805 and the neighbor cell channel estimator 815 respectively.
  • the serving cell channel estimator 805 estimates the channel to the serving base station and outputs the estimated channel value to the serving cell PMI selector 807 and the CQI generator 809 such that the serving cell PMI selector 807 and the CQI generator 809 output the positive PMI and CQI for the serving base station 503.
  • These positive PMI and CQI are input to the serving cell feedback generator 811 such that the serving cell feedback generator 811 outputs the first feedback information containing the CQI and positive PMI.
  • the negative PMI is input to the neighbor cell feedback generator 815 such that the neighbor cell feedback generator 815 outputs the second feedback information containing the negative PMI.
  • the mobile station 501 multiplexes the data and control information and the first feedback information containing the CQI and positive PMI by means of the multiplexer 831 and then transmit the multiplexed signal to the serving base station 503 by means of the transmission signal processor 835.
  • the mobile station 501 also transmits the negative PMI to the neighbor base station 507 by means of the transmission signal processor 835.
  • the serving base station 503 analyzes the signal transmitted by the mobile station
  • the cluster scheduler 505 is an independent network element.
  • the base stations can be connected to the cluster scheduler 505 through a wired or wireless link. Accordingly, the serving base station 503 reports the first feedback information acquired by the in-cell CQI/PMI receiver 911 to the cluster scheduler 505.
  • the second feedback information is received by the neighbor base station
  • the second feedback information is output to the out-cell PMI receiver 913.
  • the neighbor base station 507 also reports the second feedback information to the cluster scheduler 505.
  • the cluster scheduler 505 makes a scheduling and beamforming decision based on the feedback information reported by the serving and neighbor base stations 503 and 507 and sends the decision result to the serving and neighbor base stations 503 and 507 respectively.
  • the cluster scheduler 506 makes the scheduling and beamforming decision in consideration of the positive PMI intended to be used by the serving base station 5031 and the negative PMI intended not to be used by the neighbor base station 507.
  • the serving base station 503 Upon receipt of the decision result of the cluster scheduler 505, the serving base station 503 multiplexes the data and control information output from the data/control information generator 916 into the transmission signal by means of the multiplexer 919 and transmits the transmission signal by means of the transmission processor 921. At this time, the serving base station 503 forms a transmission beam focused to the mobile station 501 based on the beamforming decision result provided by the cluster scheduler 505. Meanwhile, the neighbor base station 507 forms a transmission beam based on the beamforming decision result provided by the cluster scheduler 505 so as not to interfere the transmission of the serving base station 503.
  • the cooperative beamforming procedure of FIG. 6 is described with the operations of the mobile station configured in FIG. 8 and the base stations configured as shown in FIG. 9.
  • the operations of the mobile station 601 for generating the first feedback information containing the CQI/PMI to be transmitted to the serving base station 603 and the second feedback information containing the PMI to be transmitted to the neighbor base station 607 are identical with those of the mobile station 501 in FIG. 5.
  • the operations of the serving base station 603 and the neighbor base station 607 for extracting the feedback information are identical with those of the serving and base stations 503 and 507.
  • the scheduler 915 integrated into the base station performs the functions of the cluster scheduler 505 of FIG. 5.
  • the scheduler 915 makes a scheduling and beamforming decision and provides the decision result to the data/control information generator 917.
  • the data/control information generator 917 generates the data and control information based on the scheduling and beamforming decision result of the scheduler 915.
  • the data and control information generated by the data/control information generator 917 are multiplexed into the transmission signal by the multiplexer 919.
  • the transmission signal is superimposed on the radio frequency signal by the transmission signal processor 921, and the radio frequency signal is transmitted through the antenna 901. At this time, the radio frequency signal is transmitted in the form of a beam focused to the mobile station 601 based on the positive PMI.
  • the scheduler 915 makes a scheduling and beamforming decision and provides the decision result to the data/control information generator 917. At this time, the scheduler 915 makes the scheduling and beamforming decision in consideration of the negative PMI reported by the mobile station 601 connected to other base station 601 and the CQI and positive CQI reported by the in-cell mobile stations (i.e. served by the base station 607).
  • the data/control information generator 917 generates the data and control information based on the scheduling and beamforming decision result of the scheduler 915.
  • the data and control information generated by the data/control information generator 917 are multiplexed into the transmission signal by the multiplexer 919.
  • the transmission signal is superimposed on the radio frequency signal by the transmission signal processor 921, and the radio frequency signal is transmitted through the antenna 901.
  • the radio frequency signal is transmitted in the form of a beam focused to the mobile station 607 based on the negative PMI reported by the mobile station 601 as well as the positive PMI reported by the mobile station 607.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)

Abstract

L'invention concerne un appareil et un procédé de formation de faisceaux coopérative dans un système de communication sans fil acceptant l'ordonnancement en fonction des canaux sur la base d'informations de rétroaction. Un procédé de formation de faisceaux dans un système de communication sans fil selon l'invention consiste à émettre, au niveau de la station mobile, des informations relatives à la condition du canal d'un canal d'une station de base de desserte à destination de la station de base de desserte et des informations relatives à la condition du canal d'un canal d'une station de base voisine; puis à former, au niveau de la station de base, un faisceau sur la base des informations relatives à la condition du canal afin d'émettre un signal et, au niveau de la station de base voisine, un faisceau permettre de transmettre un signal.
PCT/KR2009/006214 2008-10-27 2009-10-27 Appareil et procédé de formation de faisceaux coopérative dans un système de communication sans fil WO2010050718A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/126,351 US9055448B2 (en) 2008-10-27 2009-10-27 Cooperative beamforming apparatus and method in wireless communication system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1020080105131A KR20100046338A (ko) 2008-10-27 2008-10-27 이동통신 시스템의 공조 빔 형성 장치 및 방법
KR10-2008-0105131 2008-10-27

Publications (2)

Publication Number Publication Date
WO2010050718A2 true WO2010050718A2 (fr) 2010-05-06
WO2010050718A3 WO2010050718A3 (fr) 2010-07-29

Family

ID=42129442

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2009/006214 WO2010050718A2 (fr) 2008-10-27 2009-10-27 Appareil et procédé de formation de faisceaux coopérative dans un système de communication sans fil

Country Status (3)

Country Link
US (1) US9055448B2 (fr)
KR (1) KR20100046338A (fr)
WO (1) WO2010050718A2 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102387525A (zh) * 2010-08-27 2012-03-21 中国移动通信集团公司 载波配置方法、装置及系统
WO2012149178A3 (fr) * 2011-04-29 2013-01-31 Interdigital Patent Holdings, Inc. Traitement spatial en boucle ouverte
EP2562941A1 (fr) * 2011-08-24 2013-02-27 Samsung Electronics Co., Ltd. Terminal mobile et son procédé de communication, contrôleur de station de base et son procédé de commande et système de transmission multi-coopératif utilisant celui-ci et procédé associé
US20140010169A1 (en) * 2011-03-24 2014-01-09 Research In Motion Limited Device-empowered radio resource assignment
JP2015506147A (ja) * 2012-02-24 2015-02-26 エヌイーシー（チャイナ）カンパニー， リミテッドＮＥＣ（Ｃｈｉｎａ）Ｃｏ．，Ｌｔｄ． チャネル品質情報を概算する方法および装置、ならびに基地局およびネットワーク中央処理デバイス
US9072106B2 (en) 2011-03-24 2015-06-30 Blackberry Limited Device-empowered radio resource selection

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8873531B2 (en) * 2010-05-03 2014-10-28 Intel Corporation Device, system and method of indicating station-specific information within a wireless communication
KR20130054662A (ko) * 2011-11-17 2013-05-27 삼성전자주식회사 이동 통신 시스템에서 백오프 펙터 값 결정 방법 및 장치
JP5785860B2 (ja) * 2011-11-30 2015-09-30 株式会社日立製作所 基地局及び干渉制御方法
US9357505B2 (en) 2011-12-26 2016-05-31 Kt Corporation Processing digital signal
US9485737B2 (en) * 2011-12-26 2016-11-01 Kt Corporation Controlling radio units to transmitting signal with different transmission power
JP5878406B2 (ja) * 2012-03-23 2016-03-08 株式会社Ｎｔｔドコモ 無線通信システム、ユーザ端末、無線基地局装置及び無線通信方法
JP6053305B2 (ja) * 2012-03-30 2016-12-27 株式会社Ｎｔｔドコモ 無線基地局、無線通信システム及び無線通信方法
KR101791270B1 (ko) * 2012-05-14 2017-11-20 삼성전자주식회사 이동통신 시스템에서 공동으로 신호를 송수신하는 통신 방법 및 장치
US9467871B2 (en) * 2012-09-28 2016-10-11 Qualcomm Incorporated Iterative coordinated beamforming systems and methods
KR20140045752A (ko) * 2012-10-09 2014-04-17 삼성전자주식회사 빔포밍을 사용하는 무선 통신시스템의 피드백 정보 송수신 장치 및 방법
KR102012250B1 (ko) 2013-06-04 2019-08-21 한국전자통신연구원 일방향 협력 채널을 통한 빔형성 방법 및 장치
US10952089B2 (en) * 2016-05-11 2021-03-16 Mitsubishi Electric Corporation Communication system
KR102344657B1 (ko) * 2016-06-30 2021-12-30 소니그룹주식회사 기지국 및 사용자 장비
US9961664B2 (en) 2016-08-10 2018-05-01 Verizon Patent And Licensing Inc. Locating customer premises equipment in a narrow beamwidth based radio access network
CN108633006B (zh) * 2017-03-17 2021-03-19 电信科学技术研究院 一种上行发送波束确定方法和装置
EP3603201A1 (fr) * 2017-03-23 2020-02-05 Telefonaktiebolaget LM Ericsson (publ) Premier noeud de réseau, troisième noeud de réseau, dispositif sans fil et procédés mis en oeuvre pour faciliter la sélection de cellules
US20190342891A1 (en) * 2018-05-01 2019-11-07 Qualcomm Incorporated Techniques for selecting network parameters based on feedback
CN110212964B (zh) * 2019-06-10 2020-03-20 深圳大学 分布式波束成形上行链路的数据传输方法及系统
US11616562B1 (en) * 2021-11-19 2023-03-28 Nokia Technologies Oy Multi-link establishment for sidelink enhancement

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060203794A1 (en) * 2005-03-10 2006-09-14 Qualcomm Incorporated Systems and methods for beamforming in multi-input multi-output communication systems
US20060233131A1 (en) * 2005-04-19 2006-10-19 Qualcomm Incorporated Channel quality reporting for adaptive sectorization
WO2007111266A1 (fr) * 2006-03-24 2007-10-04 Matsushita Electric Industrial Co., Ltd. Terminal et station de base de communication radio
US20080075196A1 (en) * 2006-06-14 2008-03-27 Samsung Electronic Co., Ltd. Apparatus and method for transmitting/receiving data in a closed-loop multi-antenna system

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7729325B2 (en) * 2005-04-05 2010-06-01 Toshiba America Research, Inc. Beamforming and distributed opportunistic scheduling in wireless networks
US8363577B2 (en) * 2005-05-13 2013-01-29 Qualcomm Incorporated Low complexity beamforming for multiple antenna systems
CN101322327B (zh) * 2005-11-29 2012-11-14 艾利森电话股份有限公司 用于在无线中继网络中中继信息的方法、设备和系统
KR20080022033A (ko) * 2006-09-05 2008-03-10 엘지전자 주식회사 프리코딩 정보 피드백 방법 및 프리코딩 방법
WO2008069547A1 (fr) * 2006-12-04 2008-06-12 Samsung Electronics Co., Ltd. Dispositif et procédé de transmission/réception d'information de retour dans un système de communcaitions mobiles à antennes réseau
US20080219370A1 (en) * 2007-03-06 2008-09-11 Texas Instruments Incorporated User equipment feedback structures for mimo ofdma
US8150399B2 (en) * 2007-12-21 2012-04-03 Intel Corporation Techniques for wireless communications networks employing beamforming
US8280444B1 (en) * 2008-02-26 2012-10-02 Adaptix, Inc. Reducing multi-cell interference using cooperative random beam forming
US8391206B2 (en) * 2008-08-07 2013-03-05 Alcatel Lucent Method of joint resource allocation and clustering of base stations

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060203794A1 (en) * 2005-03-10 2006-09-14 Qualcomm Incorporated Systems and methods for beamforming in multi-input multi-output communication systems
US20060233131A1 (en) * 2005-04-19 2006-10-19 Qualcomm Incorporated Channel quality reporting for adaptive sectorization
WO2007111266A1 (fr) * 2006-03-24 2007-10-04 Matsushita Electric Industrial Co., Ltd. Terminal et station de base de communication radio
US20080075196A1 (en) * 2006-06-14 2008-03-27 Samsung Electronic Co., Ltd. Apparatus and method for transmitting/receiving data in a closed-loop multi-antenna system

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102387525A (zh) * 2010-08-27 2012-03-21 中国移动通信集团公司 载波配置方法、装置及系统
CN102387525B (zh) * 2010-08-27 2015-04-22 中国移动通信集团公司 载波配置方法、装置及系统
US9072106B2 (en) 2011-03-24 2015-06-30 Blackberry Limited Device-empowered radio resource selection
US20140010169A1 (en) * 2011-03-24 2014-01-09 Research In Motion Limited Device-empowered radio resource assignment
US9048983B2 (en) * 2011-03-24 2015-06-02 Blackberry Limited Device-empowered radio resource assignment
WO2012149178A3 (fr) * 2011-04-29 2013-01-31 Interdigital Patent Holdings, Inc. Traitement spatial en boucle ouverte
JP2014514875A (ja) * 2011-04-29 2014-06-19 インターデイジタル パテント ホールディングス インコーポレイテッド 開ループ空間処理
US9331757B2 (en) 2011-04-29 2016-05-03 Interdigital Patent Holdings, Inc. Open loop spatial processing
EP2562941A1 (fr) * 2011-08-24 2013-02-27 Samsung Electronics Co., Ltd. Terminal mobile et son procédé de communication, contrôleur de station de base et son procédé de commande et système de transmission multi-coopératif utilisant celui-ci et procédé associé
US8934903B2 (en) 2011-08-24 2015-01-13 Samsung Electronics Co., Ltd. Mobile terminal and communication method thereof, base station controller and control method thereof, and multi-cooperative transmission system using the same and method thereof
JP2015506147A (ja) * 2012-02-24 2015-02-26 エヌイーシー（チャイナ）カンパニー， リミテッドＮＥＣ（Ｃｈｉｎａ）Ｃｏ．，Ｌｔｄ． チャネル品質情報を概算する方法および装置、ならびに基地局およびネットワーク中央処理デバイス
EP2745548A4 (fr) * 2012-02-24 2015-06-24 Nec China Co Ltd Procédé et dispositif pour estimer des données de qualité de voie, station de base et dispositif de traitement centralisé de réseau
US9450718B2 (en) 2012-02-24 2016-09-20 Nec (China) Co., Ltd. Method and apparatus for estimating channel quality information, base station and network central processing device

Also Published As

Publication number Publication date
WO2010050718A3 (fr) 2010-07-29
US20110211487A1 (en) 2011-09-01
US9055448B2 (en) 2015-06-09
KR20100046338A (ko) 2010-05-07

Similar Documents

Publication Publication Date Title
WO2010050718A2 (fr) Appareil et procédé de formation de faisceaux coopérative dans un système de communication sans fil
US12010691B2 (en) Method and apparatus for transmitting/receiving channels in mobile communication system supporting massive MIMO
WO2010005221A2 (fr) Appareil et procédé d’annulation des interférences intercellulaires dans un système de communication sans fil mimo
US10772158B2 (en) Apparatus to establish wireless backhaul connection
WO2011040773A2 (fr) Procédé d'envoi d'informations de rétroaction comp dans un système de communication sans fil et appareil terminal
WO2009136736A2 (fr) Procédé permettant d’émettre et de recevoir des données dans un système coopératif de communications mobiles à entrées multiples et sorties multiples
US9462594B2 (en) MIMO transmission method and apparatus for use in wireless communication system
KR101498048B1 (ko) 협력적 ｍｉｍｏ를 사용하는 셀 경계 사용자를 위한 자원할당 방법
KR101207570B1 (ko) 셀 간 간섭 완화 방법
US20110287791A1 (en) Wireless Communication System and Communication Control Method
WO2009096708A1 (fr) Procédé de transmission d'informations de précodage dans un système à plusieurs antennes
WO2013100565A1 (fr) Procédé et appareil pour l'émission/réception de csi-rs dans un système massivement mimo fonctionnant en mode fdd
WO2012096449A2 (fr) Procédé et appareil de transmission coopérative à plusieurs cellules
WO2014104114A1 (fr) Station de base sans fil, terminal utilisateur, procédé de communication sans fil et système de communication sans fil
WO2010079926A2 (fr) Procédé et appareil permettant de déterminer une cellule pour exécuter une transmission comp dans un environnement à plusieurs cellules
WO2009125955A1 (fr) Procédé d’adaptation de mode dans un système mimo
WO2010095890A2 (fr) Procédé d'émission et de réception d'informations de rétroaction et appareil de station mobile/station de base pour celui-ci
WO2011013965A2 (fr) Coordination d'un pmi de liaison descendante basée sur une configuration d'antenne de station de base
WO2010076949A1 (fr) Procédé de transmission de données dans un système de communication sans fil coopératif à multiples cellules
WO2011053071A2 (fr) Appareil et procédé pour attribuer des couches dans un système de communication sans fil
WO2013154352A1 (fr) Procédé et appareil d'émission et de réception d'un signal de rétroaction dans un système de communication mobile
JP2011166204A (ja) 無線通信システム、無線基地局装置および通信制御方法
US10819402B1 (en) Grouping UEs for MU-MIMO service based on commonality of primary serving carriers
WO2011122799A2 (fr) Appareil et procédé pour émettre et recevoir des informations d'état de canal dans un système de communication
WO2010124451A1 (fr) Procédé et dispositif de transmission conjointe multiutilisateur multi-station non cohérente

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09823798

Country of ref document: EP

Kind code of ref document: A2

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 13126351

Country of ref document: US

122 Ep: pct application non-entry in european phase

Ref document number: 09823798

Country of ref document: EP

Kind code of ref document: A2